NUMBERS IN COLOR

Materials for the Teaching of Mathematics Comprising Colored Rods of Various Lengths [ and Colored Discs ] Sold as a Package with One or More of the Following Printed Items: Instruction Books, Wall Charts and Film Strips Describing the Use of the Rods; [ and Discs ] Problem Books Containing Problems Solvable Through the Use of the Rods; [ and Discs ] and Charts Bearing Various Geometrical Designs (Geo-Boards)